1. Technical Field
The present invention relates to a cooling system. More particularly, the present invention relates to a cooling system applicable to a rack server.
2. Description of Related Art
Modern technology changes with each passing day and advances rapidly. The processing speed of the computers is getting faster and faster, yet the cost of the computers is getting lower and lower. Therefore, the computers are widely used in our daily life nowadays, such as the commercial servers used in business entities and the desktop computers used by individuals. In the case of commercial servers, they are independent operable, swappable computer systems. In one common arrangement, several hard drives are inserted into one enclosure, and several electronic assemblies are integrated in a single rack of a server, therefore constituting a rack server.
Because the rack server includes several electronic assemblies, and the electronic assemblies individually include numerous thermal components like hard drives, central processors, memories . . . etc, massive amount of heat is aggregated within the rack server. The aggregation of heat affects the operation stability of the system and jeopardizes the service quality of the whole system. Due to the above-mentioned drawbacks, it is then an important topic on how to dissipate heat affectivity for the rack server.
In a common computer room accommodating several servers, the temperature within the room is controlled by the air conditioner. Taking the rack server as an example, it uses inbuilt fans of the enclosure to draw the air tempered by the air conditioner into the enclosure, so as to take the heat away from the thermal components. The hot air acquired the heat from the thermal components is rejected back to the room afterwards. By discharging the hot air directly back to the room, the temperature of the computer room is raised, and the heat dissipation rate of the enclosure is lowered. On the other hand, the air conditioner has to use more power to retain the temperature at a stationary level. This completely proceeds backwardly to the trend of saving energy and reducing carbon.
In order to lower the burden of the air conditioner, the industry develops a cooling system that individually lowers the temperature of each rack server. The cooling system takes advantage of the phase changes of a refrigerant to take the heat away from the rack server, so as to lower the temperature. However, this technique requires another heat exchange process to take the heat away from the refrigerant, such as using cooling water to cool off the refrigerant. Once again, yet another heat exchange process that takes the heat away from the cooling water is required. Consequently, the power consumption still can not be reduced. What's more, the problem of refrigerant pollution is further arisen.